The IIIF probe service redirects to the streaming server

app/controllers/iiif/auth/v2/probe_service_controller.rb

@@ -23,7 +23,16 @@ def show # rubocop:disable Metrics:AbcSize
           elsif !file.readable?
             json[:status] = 404
           elsif can? :access, file
-            json[:status] = 200
+            if file.streamable?
+              # See https://iiif.io/api/auth/2.0/#location
+              json[:status] = 302
+              json[:location] = {
+                id: "#{file.streaming_url}?stacks_token=#{current_user.token}",
+                type: "Video"
+              }
+            else
+              json[:status] = 200
+            end
           else
             json[:status] = 401
             json.merge!(add_detail(file))

app/models/stacks_file.rb

@@ -51,4 +51,24 @@ def stacks_rights
   end
   delegate :rights, :cocina_rights, :restricted_by_location?, :stanford_restricted?, :embargoed?,
            :embargo_release_date, :location, to: :stacks_rights
+
+  def streamable?
+    accepted_formats = [".mov", ".mp4", ".mpeg", ".m4a", ".mp3"]
+    accepted_formats.include? File.extname(file_name)
+  end
+
+  def streaming_url
+    "#{Settings.stream.url}/#{File.join(druid_parts[1..4])}/#{streaming_url_file_segment}/playlist.m3u8"
+  end
+
+  private
+
+  def streaming_url_file_segment
+    case File.extname(file_name)
+    when '.mp3'
+      "mp3:#{file_name}"
+    else
+      "mp4:#{file_name}"
+    end
+  end
 end

config/settings.yml

@@ -17,6 +17,7 @@ cdl:
 stream:
   # max_token_age is specified in seconds
   max_token_age: 45
+  url: https://sul-mediaserver.stanford.edu/stacks/_definst_
 
 # non-IIIF images
 legacy:

spec/requests/iiif/auth/v2/probe_service_spec.rb

@@ -130,6 +130,49 @@
     end
   end
 
+  context 'when the user has access to the resource and it is streamable' do
+    let(:file_name) { 'SC0193_1982-013_b06_f01_1981-09-29.mp4' }
+
+    let(:public_json) do
+      {
+        'structural' => {
+          'contains' => [
+            {
+              'structural' => {
+                'contains' => [
+                  {
+                    'filename' => file_name,
+                    'access' => {
+                      'view' => 'world',
+                      'download' => 'world'
+                    }
+                  }
+                ]
+              }
+            }
+          ]
+        }
+      }
+    end
+    let(:stacks_uri) { "https://stacks-uat.stanford.edu/file/#{id}/#{URI.encode_uri_component(file_name)}" }
+
+    before do
+      stub_rights_xml(world_readable_rights_xml)
+      get "/iiif/auth/v2/probe?id=#{stacks_uri_param}"
+    end
+
+    it 'returns a success response' do
+      expect(response).to have_http_status :ok
+
+      expect(response.parsed_body).to include({
+                                                "@context" => "http://iiif.io/api/auth/2/context.json",
+                                                "type" => "AuthProbeResult2",
+                                                "status" => 302
+                                              })
+      expect(response.parsed_body.dig('location', 'id')).to start_with 'https://sul-mediaserver.stanford.edu/stacks/_definst_/bb/461/xx/1037/mp4:SC0193_1982-013_b06_f01_1981-09-29.mp4/playlist.m3u8?stacks_token='
+    end
+  end
+
   context 'when the requested file does not exist' do
     let(:public_json) { {} }